Overspeed brake at terminals



Aug. 9, 1932. J. DUNLOP OVERSPEED BRAKE AT TERMINALS Filed Apx il 4, .1930

Fig.1.

///////// /l////////////Ilz SEQ INVENTOR James Dunlap.

ATTORNEY JAMES DUNLOP, OF PARK RIDGE, ILLINOIS, ASSIGNOR TO WESTINGHOUSE ELECTRIC Patented Aug. 9, 1932 UNITED STATES PATENT oFF cs ELEVATOR COMPANY, A CORPORATION OF ILLINOIS ovEnsrEEn BRAKE AT TERMINALS Application filed April 4,

My invention relates to safety. systems for elevators and morefspecifically tosafety systems for preventing elevator cars from approaching their'terminals" at excessive rates of speed.

The usual safety apparatus comprises a car-safety means carried by the car and a governor device for tripping the jaws to grip the governor cable and set the car-safety means when the car travels at an excessive. rate ofspeed. p V

However, such device will not be eifective to prevent the. car from approaching the terminal at full normal speed because it be comes effective only when the car exceeds the degree of overspeed for which the device is set. It is apparent that, when a car approaches the terminal, its speed mustbe correspondingly reduced orthe control system will be unable to check the speed thereof when it arrives at the terminal. In other words, the permissible degree of overspeed is less as the car approaches its terminal than when it is traversing some intermediate portion of the hatchway. This consideration is of particular importance with reference to high-speed elevators, of which an increasing number are being installed, and it is in con-. nection with such elevators that'my invention is of special importance and utility.

It is, accordingly, an object of my invention to provide forautomatically stopping an elevator car which is approaching a terminal at an excessive rate of speed.

It is also an object of myinvention to provide means for setting thecar-safety means if the speed of the caris not sufficiently reduced as it approaches the terminal.

t ismore specifically an object of my invention to provide means which will set the car-safety means if the speed of the car is not sufficiently reduced as it approaches its termi-. nal but which will not set the car-safety means if the speedof the car is sufficiently reduced to be under the control of the elevator-control system.

According to my invention, I provide a pair of movable jaws which are so positioned that the governor cable may pass between them and which aremoved toward or away 1930. Serial No. 441,523.

connected withthe usual governor. A buttonprovided on the'governor rope in such po- 8 1131011 that it must pass between the movable aws as the car approaches itslterminal. The

actuating means is so adjusted that the jaws will permit the button to pass if the speed of the elevator car is properly reduced to permit it to safely approach the terminal, but any greater degree of speed, including the normal running speeds, will move the jaws toward each other so that the passage of the buttonis prevented. When the button is engaged by the movable jaws, the governor rope is locked, and the car-safety means is set. This ropegripping device is provided in addition to the usual governor-actuated device which is not shown.

Other objects of my invention will become evident from the following detailed descrip-i tion, taken in conjunction with the accompanying drawing, in which Figure 1 is a diagrammatic view showing an applicatlon ofmy invention to an e1e-' vator system. The various elements are shown in the positions normally assumed by them when the car is standing or moving slowly at the terminal.

Fi 2 is a v1ew,sim1lar to Fig. 1', except that it shows the elements in the various po sitionsthey will assume when the, car is operating at full speed in an intermediate portion of the, hatchway.

Referring to the drawing,the apparatus.

shown in Fig. 1 comprises an elevator car C suspended by a cable Ca passing over a hoist drum D which may be actuated and controlled in any well known manner. The means for actuating and controlling the drum D is not shown, because it is well known and illustration of it would necessarily complicate the disclosure. I

A governor cable GCpasses over a governor sheave GS at the top of the hatchway and under a sheave S at the bottom of the hatchway and is releasably secured to the carfC by a releasable tension clip 11. A governor G is associated with the governor sheaves GS and is driven thereby. The governor cable GC is driven, at a-speed corresponding 100 ropegripping to the speed of the elevator car, through the releasable clip 11, and the governor sheave GS and its associated governor G are, in turn, driven thereby. The governor G may be the governor usually provided for tripping a pair ofjaws (not shown) for gripping the governor rope and setting the ear-safety means when the car attains a certain predetermined degree of overspeed.

In accordance with my invention, 1 provide an additional pair of jaws-16 and 17 which are pivotally supported on a partition 20. The jaws 16 and 17 are so positioned that the governor rope GO passes between them, and they are biased towardth'e open position bygravity, or a pair of springs 18and 19 maybe provided for this purpose. Alever I2 i ei'a i y associ ted with th go e e nor one end thereof is pivoted on a fixed pivot P,'.whereby operatio1i of the governor at various speeds will cause the free end of the lever to beosc'illated through an arc. Hence, the free end of the lever will assume various positions, rising as the speedof the elevator car increases and falling as the speed decreases. I j v A flexible rope or suitable connecting mem ber l3'is secured, at one end, to the free end of the lever 12. The other end of the rope 13 is inthe form of an endless loop passing around pulleys 14 and 15 carried by the ,pivdtjedjaw's 1'6 and 17, respectively.

It will be apparent that, as the free end of the lever 12 is lifted, by the effect of increasifn'g' spe d, the rop is will be drawn taut, thereby drawing the pulleys 14 and 15 and the corresponding jaws 1'6"and 1? toward each other. As the end of the lever 12'is lowered in response to decreasing speed, the rope 13 "will be sla'chened, jthereby permitting the jaws ity and 17 to fall apart, or to be pulled apart by springs 18 and 19, to their open .pos'itions (as shown in Fig. 1). W

A button 21;is secured to 'thek'gove'rnor cable in such position that it must pass between the jaws fwhen the car approadhes the termi- The button is of such shape that it will be positively engaged by the aws 16 and 17 when they are in the closed positionshown in Figr2, --I-t.is tobenoted-that,-a1thoughthe jaws, in their closed positions, constitute an impassable barrier to the button carried by thegovernor cable, the cable itself may pass freely therebetween, until the button 2-1 is carried into the "engagin position. When in Fig. 1, the button may pass freely between them to the positionit mustoccupy'when the o'ar is at'the termina1.- i

A car-'s'afety device 25-isicarrifed'hythe car a d is adtuatedfliy m'eans o f a cable aewhih' similar to that disclosed in my Patent No. 1,598,065, issued August 31, 1926.

My invention may be better understood when considered in connection with an assumed operation thereof.

Assuming that the car is standing at the terminal, the various parts'f the system will occupy the positions shown in Fig. 1. As the car starts upwardly and approaches an intermediate position, the various elements will assume the positions shown-in Fig. 2.

It will be noted that the button 21 on the governor cable has passed between the jaws 1,6:and 17. Because of the speed attained by the car, "as it moves up the hatchway, the

' governor is driven at such high speed that the Weighted'bal-ls 23 and 24 are thrown outward, thereby lifting the free end of the lever 12 and drawing the jaws toward each other to their closed positions.

Assume that the car in Fig 2 is iowreturning toward the lower terminal, and that the button 2 1 is approaching the jaws l6 and 17. In the normal operation of the system, the speed of the elevator car will be gradually reduced as it approaches the, terminal. The adjustment of the governor G and the jaws 16 and 17 and the position of the button 21 on the governor cable will besuch that the jaws will normally assume their open posi- .tions (shown in Fig. l) in time to permit the button 21 to pass between them. A

If, however, the speed of the elevator continues undiminis'hed as it approaohes the terminal, the jawswi'll remain in their closed positions. As the button approaches the closed jaws, it will be brought into positive engagement with them, thereby locking the governor cable against further movement, andpu-llingitfree from thereleasable clip 11. Continued movement of the elevator car will cause the safety cable-26 to beunreeled from the safety drum on the car,ithereby setting the braking device and bringingithe car'to a stop.

The operation of the elevator car, as it-approaches its terminal, has been considered and it has been shdwn'thau'under normal conditions, the operator will so *reduce the speed that my device will not be actuated to set the car-safety-device. It has been shown, however, that, if the operator fails to :properly reduce thespeed of the car aslit approaches the terminal, mysafety device'w ill 1001; the gov ernor cable and set theAcar-safety device, thereby stopping the oar automatically. Although I have. shown.,-and described a specific embodiment'of myin-vention, I am fully aware that many modifications thereof are poss ble, My, invention, therefore, is notto be restricted exceptiinsofar as is necessitated by the prior art and by the spititof the appended claims. A I s I olaim'as my invention: 1. In combination with anelevator oan, a

braking device "carried 'therehy, a 'speedme sponsive device actuated in accordance with the speed of the elevator car for applying the braking device when the car overspeeds, and means actuated thereby for applying the braking device if the speed of the car is not properly reduced as the car approaches a terminal.

2. In combination with an elevator car, and a braking device carried thereby, a speed responsive device for applying the braking device when the car overspeeds, an engaging member actuated to an engaging or disengaging position by said speed responsive device in accordance with the speed of the car, a cooperating engaging member moved into or away from engaging relation with said first engaging member in accordance with the position of the car, and means responsive to cooperative engagement of said first and second engaging members for applying said braking device to stop the car.

3. In combination with an elevator car, a braking device carried thereby, and a speedresponsive device actuated in accordance with the speed of the car for applying said braking device when the car overspeeds, ofan engaging member actuated to an engaging or disengaging position by said speed-responsive device in accordance with the speed of the car, a cooperating engaging member moved into or away from engaging relation with said first engaging member in accordance with the position of the car, and means responsive to cooperative engagement of said first and second engaging members for applying said braking device to stop the car.

4. In combination with an elevator car, a braking device carried thereby, a speed-responsive device, means for actuating said speed-responsive device at a speed corresponding to the speed of the car comprising a cable passing over a sheave associated therewith and means for releasably securing said cable to the elevator car, an engaging member actuated into engaging or disengaging position by said speed-responsive device in accordance with the speed of the elevator car, a cooperating engaging-member carried into or away from engaging position by said cable in accordance with the position of the car, and means actuated in response to the engagement of said members for applying said braking device to stop the car.

In testimony whereof, I have hereunto subscribed my name this l7th day of March,

JAMES DUNLOP.

DISCLAIMER 1,871,213.James Dunlap, Park Ridge, Ill. OVERSPEED BRAKE AT TERMINALS. Patent dated August 9, 1932. Disclaimer filed June 1, 1934, by the assignee, VVestinghouse Electric Elevator Company. Hereby enters this disclaimer to claim 1 of the patent specification which is in the following Words, to Wit:

1. In combination With an elevator car, a braking device carried thereby, a

speed-responsive device actuated in accordance With the speed of the elevator car for applying the braking device when the car overspeeds, and means actuated thereby for applying the braking device if the speed of the car is not properly reduced as the car approaches a terminal.

[Oficial Gazette June 19, 1.934.] 

